This OCaml-library interfaces the PCRE (Perl-compatible regular
expression) library which is written in C. it can be used for matching
regular expressions which are written in the PERL style.
 
It is reentrant - and thus thread safe. This is not the case with the
"Str" module of OCaml, which builds on the GNU "regex"-library. Using
reentrant libraries also means more convenience for programmers. They do
not have to reason about states in which the library might be in.
 
The high-level functions for replacement and substitution, all
implemented in OCaml, are much faster than the ones of the "Str"-module.
In fact, when compiled to native code, they even seem to be
significantly faster than those of PERL.
